Not at all surprisingly, there's an ABABSoft logo at 0x12F010 in the 15-in-1 ROM.
Edit: And it's right above the War/Contra Force/Guevara/Golden Axe menu.
Edit #2: And that 4-in-1 cartridge is listed on
ABABSoft's archived site, of course.
There's another menu hidden in there that has Titenic, RoboCop, and... The Avengers. The actual cart listed on ABAB's site replaces the latter with Ghostbusters II, which makes a lot more sense, given that the Avengers movie only comes out this year.
Also not at all surprisingly, The Hummer still has Somari's goalpost sign and "SOMARI TEAM PRESENTS" in its graphics.